Tag Archives: Weddell Sea

THE WEDDELL SEA AGAIN

2 Jan

Happy New Year!!

This January, Professor Julian Dowdeswell of the Scott Polar Research Institute will lead an international research team in the long planned expedition to the Weddell Sea. This expedition aims to investigate ice shelves around the Weddell Sea, particularly the Larsen C Ice Shelf. It also hopes to locate the wreck of Shackleton’s ship Endurance, which sank in the area in 1915.

The expedition’s progress and achievements will be followed internationally – in addition the Royal Geographical Society has created an educational programme aimed at engaging the interest of children from primary level upwards.

The Weddell Sea was discovered in 1823 by James Weddell, the British sea captain/ sealer, who sailed as far south as 74°15´S. It is a vitally important ecosystem – penguins, seals, whales, krill, corals and sponges thrive there. It is shaped as a huge bay; Coats Land (discovered by William Speirs Bruce in 1904) is at one extremity, the Antarctic Peninsula is on the other. It has been described as ‘the most treacherous and dismal region on earth’.[i]

An important aim will be to investigate the shapes of the ice shelf bases. Ice shelves stop ice from flowing outwards from the continent. Thinning of the ice shelves results in increased flow from the interior, which, in turn, causes a rising global sea level. The sea floor will be examined to assess the stability of the ice shelf.

Although the general circulation of oceans is determined by wind driven currents, the Weddell is one of few locations where deep and bottom water masses contribute to global thermohaline circulation. Bottom water is the lowest water mass with distinct characteristics in terms of physics, chemistry, and ecology and a temperature of -0.7 °C or colder. The thermohaline circulation is the motor of deep ocean currents and is driven by density gradients influenced by surface heat and freshwater fluxes. The description relates to thermo- temperature-and –haline, salt content.

The Larsen Ice Shelf, in the northwest part of the Weddell Sea, is named after Captain Carl Anton Larsen, master of a Norwegian whaling vessel who sailed along the ice front as far as 68°10′ S. in 1893. From north to south segments of the shelf are called Larsen A, B, and C (the largest), and Larsen D, E, F and G.

The 2019 expedition is focused on the Larsen C ice shelf from which a giant ice berg calved off in July 2017 (twice the area of Luxembourg), reducing the size of the iceshelf by approximately12%.

 

 

 

Dowdeswell and Shears[ii] explain in the ‘Geographical’ that measurements will be taken of salinity and temperature of the sea adjacent to the shelves, samples of marine life will be obtained and the sea ice thickness will be measured by aerial drones. Autonomous Underwater Vehicles will make echo soundings of the underwater shape of the ice shelf base, the roughness of which is a vital parameter in numerical modelling of future ice shelf stability. Ernest Shackleton’s Ship will be searched for.

Whether the team will be able to achieve these aims is uncertain — the conditions are so unpredictable that attempts to navigate south could be unsuccessful, but this expedition is of pivotal importance in attempting to obtain long-term prognostic information relating to global warming. I hope this important analysis of the Weddell Sea will be successfully accomplished.

[i] Henry, T.R.,1950,The White Continent

[ii] Dowdeswell, J. Shears, J. 2019, Geographical, p.10

 

 

 

 

Advertisements

Recognition for William Speirs Bruce

30 May

I have just spent another five days in Edinburgh; at the National Museum and the Edinburgh University Library, continuing my researches on William Speirs Bruce. I find it truly amazing how much information there is on the man, but how little his name is recognised — even in Edinburgh!
Now however, he has received some public recognition. His major contribution to Science was the ‘Scotia’ Expedition, which went to the Weddell Sea and wintered in the South Orkneys. The expedition was successful scientifically: discoveries that were made changed the way the geography of Antarctica was understood, the seas around the Antarctic were explored, a scientific base was set up on South Georgia (which continues today), 1100 species of animal were catalogued of which 212 of them were previously unknown, miles & miles of unknown ocean were explored.
When he returned to Edinburgh Bruce needed to house Scotia’s Antarctic data and specimens. Also, he needed to amalgamate this collection with collections he had made previously on five visits to Arctic. He took a storage area, contiguous with The Surgeons Hall of the Royal College of Surgeons, which he named the Scottish Ocenographical Laboratory, and from here, he worked endlessly and tirelessly in the preparation of six scientific volumes, and a log book,the seventh,which was on the day to day activities of the voyage, This was a Herculean task and took years and years of work. The scientific volumes were published between 1909 and 1920. Bruce’s Log, the narrative of the voyage, was not published until 1992.
The Oceanographic Laboratory had to be closed due to lack of funds before Bruce died in 1921 and, after his death, Bruce drifted into obscurity in the minds of the general public,
Now however, and at last, Bruce has been recognised by the naming of a laboratory at the British Antarctic Survey Research Station on Signy Island in the South Georgia Islands. A commemorative plaque has been erected in the laboratory. The news was given to Bruce’s great, great grandsons at a meeting hosted by the Oban-based Scottish Association for Marine Science in its William Speirs Bruce lecture room.
Dr John Dudeney, an Antarctic specialist, made the approach to the Brutish Antarctic Survey. It is a long needed recognition for one, who struggled ceaselessly, and with insufficient funds, to draw public attention to the wonders and opportunities of Antarctica.

WILLIAM SPEIRS BRUCE

14 Oct

I have now started work on Bruce who led the ‘Scotia’ expedition (1902-04), a scientific expedition in the South Orkneys and the Weddell Sea. I would welcome any input.
Bruce seems to have had two outstanding enthusiasms; Firstly, natural sciences (he gave up the medical studies that he seems to have pursued in a desultory fashion for some years, to embrace the financial uncertainties of a scientific future) and secondly, a passionate Scottish Nationalism.
There are no obvious indicators for these passions;although Bruce’s father Samuel was born in Edinburgh, he grew up in London. Bruce himself was English born and educated. His overwhelming interest in natural science and Scotland seems to have started when he attended summer courses in biology in Edinburgh. These were organised by the inspirational Patrick Geddes. Geddes was an ecologist and promoted a holistic approach to the environment. In these courses Bruce met the foremost natural scientists of the day. His imagination and enthusiasm were caught. Aged 20, Scotland became his home and had his longterm loyalty.
Bitterness towards the South came later, no doubt fueled by Sir Clements Markham’s provocative reply to Bruce’s announcement, in 1901, that he planned a Scottish expedition to Antarctica to leave at roughly at the same time as Sir Clements’ baby. S.S ‘Discovery’
Sir Clements wrote…..’I do not understand why this mischievous rivalry should have been started and I trust you will not connect yourself with it…..’
Such comments inevitably stiffened the determination of the Scottish supporters of the scheme. ‘Scotia’ unusually, was fully financed by private, mostly Scottish backers.
The expedition was a success scientifically and a new land was discovered in the east of the Weddell Sea. He called this Coats Land after his principle backers.
Beyond Scottish borders Bruce is not as well known as other British explorers of the Heroic Era, although Professor David Munro mounted an important celebratory centenary exhibition.
Bruce deserves more recognition

Shipworms

27 Aug

Shipworms which destroy wood. do not survive in Antarctic waters. This is because a Front, at the junction of the polar and warmer waters (as well as currents that circulate round the continent), acts as a barrier that blocks the invasion of these destructive mollusks.

When a Norwegian study led by Thomas Dahlgreen, (1), left wood on the Antarctic shelf for over a year, the wooden planks remained intact.

Trees have not grown on the continent for millions of years and it seems that off shore Antarctica is an inhospitable habitat for wood borers.

The fascinating question is whether wrecks in the Weddell Sea could be recovered. The prospect seems remote, given the depth of the Weddell Sea and the pack ice, but nevertheless the suggestion remains a tantalising prospect. When Shackleton’s ‘Endurance’ was crushed by the pack and sunk in November 1915 (She’s going, boys), she was thought to be lost irrevocably. Could she still be lying, crushed but defiant under the Antarctic waters?

(1) Thomas Dahlgreen. Proceedings of the Royal Society. August, 2013